Which model is better: Claude 3.5 Sonnet or Claude Opus 5.5?
Claude 3.5 Sonnet is 25.0% cheaper for input tokens ($3.00 vs. $4.00 per 1M tokens) and $15.00 vs. $20.00 for output tokens (1.3x cost advantage). In terms of operational performance, Claude 3.5 Sonnet delivers lower response latency at 310ms TTFT (370ms faster than Claude Opus 5.5) with 80 vs. 95 tok/s throughput. Claude Opus 5.5 leads coding evaluations at 89.9% SWE-bench Verified vs. 49.0% for Claude 3.5 Sonnet and 93.2% vs. 59.4% on GPQA Diamond.
Verified daily via automated API latency tests and official documentation.
Zero-Shot RAG Verified
Verified Performance & Unit Economics Delta (12 Dimensions)
Daily synchronized metrics across token pricing, prompt cache economics, latency, throughput, and 5 capability benchmarks.
Metric / Dimension
Claude 3.5 Sonnet
Claude Opus 5.5
Net Delta / Advantage
Input Cost / 1M Tokens
$3.00
$4.00
Claude 3.5 Sonnet is 1.3x cheaper
Output Cost / 1M Tokens
$15.00
$20.00
Claude 3.5 Sonnet (25.0% lower)
Prompt Cache Read / 1M
$0.300
$0.200
Claude Opus 5.5 is 1.5x cheaper
Prompt Cache Write / 1M
$3.75
$5.00
Claude 3.5 Sonnet is 1.3x cheaper
Context Window (Max Output)
205k (8k out)
1,024k (128k out)
Claude Opus 5.5 (5.0x larger context)
Avg TTFT Response Latency
310ms
680ms
Claude 3.5 Sonnet (370ms faster)
Generation Speed (Throughput)
80 tok/s
95 tok/s
Claude Opus 5.5 (+15 tok/s faster)
SWE-bench Verified (Coding)
49%
89.9%
Claude Opus 5.5 (+40.9% lead)
GPQA Diamond (PhD STEM)
59.4%
93.2%
Claude Opus 5.5 (+33.8% lead)
MMLU-Pro (Multi-Discipline)
78%
92.1%
Claude Opus 5.5 (+14.1% lead)
MATH-500 (Quantitative Logic)
78.3%
98%
Claude Opus 5.5 (+19.7% lead)
Inference Value Score (IVR)
46.2 / 100
57.8 / 100
Claude Opus 5.5 (+11.6 pts)
Interactive Monthly Token Economics & ROI Forecaster
Model production workloads across prompt, completion, and cached context tokens, or switch models on the fly.
Choose Claude Opus 5.5 (Anthropic) for top-ranked frontier intelligence leader for autonomous multi-step agentic coding, repository-scale migrations, and complex scientific reasoning at a 40% lower workload cost than Opus 5 — offering a 1,024k context window, 680ms TTFT, and $4.00/1M input pricing ($0.200/1M cached reads).
Which is cheaper: Claude 3.5 Sonnet or Claude Opus 5.5?
Claude 3.5 Sonnet is cheaper at $3.00/1M input tokens ($15.00/1M output) compared to $4.00/1M input ($20.00/1M output) for Claude Opus 5.5.
Which model has lower TTFT latency and higher tok/s throughput: Claude 3.5 Sonnet or Claude Opus 5.5?
Claude 3.5 Sonnet delivers faster first-token latency at 310ms TTFT (80 tok/s throughput) compared to 680ms TTFT (95 tok/s) for Claude Opus 5.5.
How do Claude 3.5 Sonnet and Claude Opus 5.5 compare on SWE-bench coding and GPQA Diamond reasoning?
On SWE-bench Verified software engineering, Claude 3.5 Sonnet scores 49% versus 89.9% for Claude Opus 5.5. On GPQA Diamond graduate-level STEM reasoning, Claude 3.5 Sonnet scores 59.4% versus 93.2% for Claude Opus 5.5 (and 78.3% vs 98% on MATH-500).
When should you choose Claude 3.5 Sonnet?
Choose Claude 3.5 Sonnet (Anthropic) for legacy enterprise workflows, code review pipelines, and human-like content generation — offering a 204k context window, 310ms TTFT, and $3.00/1M input pricing ($0.300/1M cached reads).
When should you choose Claude Opus 5.5?
Choose Claude Opus 5.5 (Anthropic) for top-ranked frontier intelligence leader for autonomous multi-step agentic coding, repository-scale migrations, and complex scientific reasoning at a 40% lower workload cost than Opus 5 — offering a 1,024k context window, 680ms TTFT, and $4.00/1M input pricing ($0.200/1M cached reads).
